The invention relates to improvements in rotary exchange equipment wherein particulate material is carried in a rotary drum and subjected to a drying or cooling process, and more particularly to an improved structure wherein the treatment of particulate material is enhanced.
The function of a cooler, for example of a tube cooler or of a satellite cooler, is to cool a hot product such as cement clinker coming from a kiln to the farthest possible degree. Also the function is simultaneously heat the cooling air flowing through the cooler to the farthest possible degree before it usually enters into the kiln. Such air is referred to as secondary air and is employed there as combustion air. The degree of cooling depends on the heat transmission between the product and the cooling or secondary air. The quantity of product, the quantity of air, the product temperature and the air temperature, each upon entry into the cooler, as well as the product qualities such as the granulation, cannot be influenced by the cooler. The cooler efficiency is essentially defined by three conditions, the size of the heat transmission surfaces, the dwell time of the product in the cooler, and dust formation and dust circulations.
It is known to enhance the efficiency of a tube cooler or of a satellite cooler by integrating lifter shovels or lifter ledges composed of wear-resistant steel. These lift the hot cement clinker and drop it into the stream of cooling air and an intimate contact of the cooling air with the clinker being thereby achieved. Such baffles that scatter the hot product have previously been utilized only in the central region of the cooling tube as well as the end region of the cooling tube at the product discharge side. Such baffles cannot be employed in the hot zone of the cooler adjoining the kiln because a scattering of the product material by the cooling airstream must be absolutely avoided in this hot zone. In this zone the temperature difference between hot material and cooling air is also greatest because the cooling air would otherwise be loaded with dust which diminishes the heat transmission in the hot cooler zone and undesirably transports the cooling air/secondary air back into the sintering kiln. This leads to a deterioration of the efficiency of the overall process.
It is likewise known to improve the heat transmission using what are referred to as cross baffles. These baffles are preferably utilized for superfine material that is to be scattered as little as possible. The utilization of such cross baffles in the hot zone of a cooler would lead to mechanical problems and would be disadvantageous for the distribution of the product onto the cross-section. Only mushroom-shaped or cone-shaped baffles have been utilized in the hot zone of the cooling tube and these essentially having the job of blending the nodule of product material lying in the cooling tube without a lifting effect in order to achieve a better heat transmission by radiation by creating new product surfaces. The large surface of product material required for a good heat transmission, however, is not achieved in this way, so that the heat transmission especially in this hot zone of the cooler is still in need of improvement.
An object of the present invention is to increase the thermal efficiency of a rotary cooler, particularly in the critical hot zone without having the accept a noticeable increase in the dust load on the gas stream or an increase in the dimensions of the rotary cooler.
A further object of the invention is to improve the thermal efficiency in the rotary drum for the treatment of a granular or partly scatterable material in the tube cooler, satellite cooler, rotary tubular kiln, drum dryer or the like.